3. Aimcor Pureheat briquettes, manufactured by Applied Industrial Materials UK Limited at Immingham, North East Lincolnshire, or manufactured by Oxbow Carbon & Minerals UK Limited at Windsor House, Cornwall Road, Harrogate, North Yorkshire, which—
(a)comprise anthracite (as to approximately 60% of the total weight), petroleum coke (as to approximately 25% of the total weight) and binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 250°C;
(c)are pillow-shaped briquettes with a single line indentation on one side and a double line indentation on the reverse side;
(d)have an average weight of 75 grams; and
(e)have a sulphur content not exceeding 2% of the total weight.